The four major functions of hormones are

1.so first. Amine-derived hormones are derivatives of the amino acids tyrosine and tryptophan. Examples are catecholamines and thyroxine. 
2. second. Peptide hormones consist of chains of amino acids. Examples of small peptide hormones are TRH and vasopressin. Peptides composed of scores or hundreds of amino acids are referred to as proteins. Examples of protein hormones include insulin and growth hormone. 
3. third. Steroid hormones are derived from cholesterol. The adrenal cortex and the gonads are primary sources. Examples of steroid hormones are testosterone and cortisol. Sterol hormones such as calcitriol are a homologous system. 
4. and fourth Lipid and phospholipid hormones are derived from lipids such as linoleic acid and phospholipids such as arachidonic acid. The main class is the eicosanoids, which includes the widely-studied prostaglandins.

1. Hormones are specialized substances that coordinate the activities of specific cells in certain areas of the body. 
2. They make ensure growth occurs properly.
3. Hormones make sure that reproduction occurs at the best possible time.
4. Hormones functions is to Ensure that development and maturation occur properly and on time. 

The light is great source of energy